PROJECT SUMMARY The long term goal of the project is to develop a combined intraoperative aberrometer and Optical Coherence Tomography (OCT) system optimized for cataract surgery guidance. Currently, surgeons rely on eye biometry performed before surgery to make their best guess as to the correct intraocular lens (IOL) power and how to position it inside the eye. The current approach does not deliver the visual outcomes that modern implants and instrumentation for cataract surgery, including premium IOLs and femtosecond lasers, should provide, while patient expectations have never been higher. The proposed technology will enable intraoperative ocular biometry during cataract surgery. In the long term, our approach will help improve the visual outcome of cataract surgery. As a first step, the objective of this exploratory project is to demonstrate the proof of principle of a novel approach to combine an OCT system and a wavefront aberrometer. Specific Aim 1: To demonstrate the proof-of-principle of OCT-based wavefront aberrometry. We will design a modular aberrometer that takes advantage of the OCT beam to acquire wavefront aberrometry measurements. As a first step, we will mount the system on a slit-lamp stand to make it suitable for preliminary studies on human subjects. Specific Aim 2: To evaluate the performance of the OCT-based wavefront aberrometer in a preliminary human subjects study. Refractive measurements obtained with the proposed system will be compared to measurements obtained with a commercial device.